man pthread_mutex_getprioceiling () - get and set the priority ceiling of a mutex (REALTIME THREADS)
NAME
pthread_mutex_getprioceiling, pthread_mutex_setprioceiling - get and set the priority ceiling of a mutex (REALTIME THREADS)
SYNOPSIS
#include <pthread.h>
int pthread_mutex_getprioceiling(const pthread_mutex_t *restrict
mutex,
int *restrict prioceiling);
int pthread_mutex_setprioceiling(pthread_mutex_t *restrict mutex,
int prioceiling, int *restrict old_ceiling);
DESCRIPTION
The pthread_mutex_getprioceiling() function shall return the current priority ceiling of the mutex.
The pthread_mutex_setprioceiling() function shall either lock the mutex if it is unlocked, or block until it can successfully lock the mutex, then it shall change the mutex's priority ceiling and release the mutex. When the change is successful, the previous value of the priority ceiling shall be returned in old_ceiling. The process of locking the mutex need not adhere to the priority protect protocol.
If the pthread_mutex_setprioceiling() function fails, the mutex priority ceiling shall not be changed.
RETURN VALUE
If successful, the pthread_mutex_getprioceiling() and pthread_mutex_setprioceiling() functions shall return zero; otherwise, an error number shall be returned to indicate the error.
ERRORS
The pthread_mutex_getprioceiling() and pthread_mutex_setprioceiling() functions may fail if:
- EINVAL
- The priority requested by prioceiling is out of range.
- EINVAL
- The value specified by mutex does not refer to a currently existing mutex.
- EPERM
- The caller does not have the privilege to perform the operation.
These functions shall not return an error code of [EINTR].
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
pthread_mutex_destroy() , pthread_mutex_lock() , pthread_mutex_timedlock() , the Base Definitions volume of IEEE Std 1003.1-2001, <pthread.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .